The most popular coffee making machines in use today are the drip coffee makers. A drip coffee maker conventionally has a filter support that is held positioned above a coffee pot. A filter shaped to conform to the inside dimensions of the filter support is inserted into the basket and fresh ground coffee is measured into the filter. Hot water is introduced above the filter, the hot water percolates downwardly through the fresh ground coffee and hot coffee is collected and discharged into a coffee pot.
The filters used with drip coffee pots are of two basic types. They are essentially either cone shaped with the lower end of the cone designed to be inserted down into the filter support or they are of a basket type that have flat bottoms and fluted side walls. Both types of filters are open at their upper ends to provide access for adding fresh grounds coffee and hot water. This invention is concerned only with drip coffee makers of the basket type and, more particularly, it relates to containers for storing and dispensing basket coffee filters.
Basket-type coffee filters are packaged for sale in nested, tightly compacted stacks. The basket filters conventionally are cut from a stack of flat filter papers and the flat stack is then configured into the form of a plurality of baskets with fluted side walls. In the cutting and forming operations the individual filters in a stack become enmeshed with adjacent filters at their cut edges often making it difficult to separate one filter from the next. Many people, especially the elderly and those who have lost some of the tactile sense in their fingers, find it difficult to separate and remove a single filter from the nested stack. Often several filters stick together when removed from the stack and they too must be separated from each other.
Suppliers of filters recognize that separating filters is, at best, a bothersome task and have tried to make the process easier. Some of them have provided low cost plastic tweezers with rubber or plastic tips as a bonus in a filter package. The innermost of the nested filters can be grasped by the tweezers and removed from the stack. Other filter manufacturers supply a cardboard tab coated on one side with a sticky substance that can grasp the uppermost filter for removal.
Other devices have been proposed to make it easier to separate nested coffee filters. Some of them utilize an articulated finger with a high friction surface at its end. The finger may be mounted on the under side of a hinged lid of a container and, when the lid is opened, the articulated finger engages the inside surface of the top filter paper and detaches it from the stack. Two examples of this type are illustrated in U.S. Pat. Nos. 5,197,630 and 5,687,876. The former patent is of interest since it contains a short bibliography of the patents of the prior art that deal with this problem. The latter of the two patents demonstrates the potential complexity of using an articulated finger since, it is noted, drawings with thirty-one figures were required to show the details of the patented device.
U.S. Pat. No. 4,874,112 is noteworthy for its simplicity. The patent teaches that the outside edges of the filters can be splayed out by folding a stack inside out and then returning the stack to its original configuration. The geometry of this movement cause the filters to move relative to each other when the stack is flexed making it easier to grasp an individual filter.
U.S. Pat. No. 4,674,635 shows an apparatus for securing coffee filters when they are folded over approximately along a diameter of the stack of filters. The folded filter stack is clamped in this position by a weighted and spring loaded hold down plate. The device apparently suffers from lack of reliability as evidenced by the suggestion that rubber bands may be used to retain the position of the elements should the springs fail.